add validator for prefix
diff --git a/settingdialog.h b/settingdialog.h
index ac63777..f9fc31c 100644
--- a/settingdialog.h
+++ b/settingdialog.h
@@ -1,6 +1,7 @@
 #ifndef SETTINGDIALOG_H
 #define SETTINGDIALOG_H
 #include "ui_settingdialog.h"
+#include <QKeyEvent>
 
 class SettingDialog : public QDialog, private Ui::SettingDialog
 {
@@ -8,6 +9,7 @@
 
 public:
   SettingDialog(QWidget *parent = 0, QString nick = QString("NULL"), QString chatroom = QString("NULL"), QString prefix = QString("NULL"));
+  virtual void keyPressEvent(QKeyEvent *e);
 
 private slots:
   void update();